Internal combustion engines are commonly used in vehicles and industrial machinery. These engines include an intake manifold, an exhaust manifold, at least one cylinder defining a combustion chamber having a piston and a spark plug, and a valve system for delivering the proper air/fuel mixture to the combustion chamber from the intake manifold and removing exhaust gases from the combustion chamber to the exhaust manifold after combustion.
Several rotary valve system designs for internal combustion engines have developed over the years to reduce engine inefficiencies associated with conventional valve systems and to increase engine power output. For example, U.S Pat. No. 4,879,979 teaches a valve system including a rotatable valve shaft having intake and exhaust slots formed through the shaft for intermittently connecting the intake manifold to the combustion chamber and the combustion chamber to the exhaust manifold. This design includes a complicated cooling system which requires a liquid coolant to flow through the center of the shaft. U.S. Pat. No. 4,944,261 and U.S. Pat. No 4,953,527 describe rotary valve systems having individual rotatable valve chambers for delivering fuel to and removing exhaust from the combustion chamber. These designs, however, require complicated manufacture which substantially increases total engine cost.